Metallic Bonding

Metallic Bonding

Metallic bonding occurs in metals and explains why they have properties like high melting points, conductivity, and malleability. In a metallic bond, positive metal ions are held together by a sea of delocalised electrons.

 

What is metallic bonding?

 

  • Metals consist of positive ions arranged in layers
  • The outer electrons become delocalised (free to move)
  • This creates a sea of electrons that surrounds the ions
  • There is a strong electrostatic attraction between the positive ions and negative electrons
 

Structure of metals

 

  • Giant metallic lattice structure
  • Electrons can move throughout the structure
  • Bonds are strong and require lots of energy to break
 

Properties of metals (explained by metallic bonding)

Property

Reason

High melting/boiling points

Strong electrostatic forces between ions and delocalised electrons

Good conductors of electricity

Delocalised electrons carry charge through the structure

Good conductors of heat

Free electrons transfer energy quickly

Malleable and ductile

Layers of ions can slide over each other without breaking bonds

Strong and dense

Closely packed ions in regular rows

Alloys

 

  • An alloy is a mixture of metals or a metal with another element
  • The different-sized atoms distort the layers
  • This prevents sliding, making alloys stronger than pure metals
 

Examples:

  • Brass = copper + zinc
  • Steel = iron + carbon

Questions 

  1. What particles are involved in metallic bonding?
  2. Why can metals conduct electricity?
  3. What makes metals malleable?
  4. What is an alloy?
  5. Why are alloys harder than pure metals?

Summary 

  • Metallic bonding is the attraction between positive metal ions and delocalised electrons
  • Metals have a giant lattice structure with a sea of electrons
  • They are strong, malleable, and conduct heat and electricity
  • Alloys are mixtures that are usually stronger than pure metals